The population of the planet magrathea doubles every 40 years. in the year zero the population was 20 million. the total land area of magrathea is 200 million square kilometers. one square kilometer of land can house 200 magratheans. land that is not used for housing is used for agriculture. write down an equation whose solution is the year in which there are 30 m2 of agricultural land available for each inhabitant. solve this equation.

Two loudspeakers, 5.5 m apart and facing each other, play identical sounds of the same frequency. you stand halfway between them, where there is a maximum of sound intensity. moving from this point toward one of the speakers, you encounter a minimum of sound intensity when you have moved 0.33 m . assume the speed of sound is 340 m/s.part a) what is the frequency of the sound? part b) if the frequency is then increased while you remain 0.21 m from the center, what is the first frequency for which that location will be a maximum of sound intensity? express your answer to two significant figures and include the appropriate units.